How to enable/disable DNS Settings menu for a customer in Plesk?
For a particular subscription:
Subscriptions > example.com > Customize > Permissions > check/uncheck DNS zone management
For all subscriptions that associated with a particular Service plan:
Service Plans > [Service Plan name] > Permissions tab > check/uncheck DNS zone management
This way DNS Settings menu for subscriptions assigned to a particular service plan will be hidden under a customer's account but Plesk admin will still be able to see DNS Settings on a domain. So the menu will be hidden for customers only.